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Browse subject: demonstration forests
Number of records: 90

Comparisons of land cover and LAI estimates derived from ETM+ and MODIS for four sites in North America: a quality assessment of 2000/2001 provisional MODIS products
About this Resource: The MODIS land science team produces a number of standard products, including land cover and leaf area index (LAI). Critical to the success of MODIS and other sensor products is an independent evaluation of product quality. In that context, we describe a study using field data and Landsat ETM+ to map land cover and LAI at four 49-km2 sites in North America containing agricultural cropland (AGRO), prairie grassland (KONZ), boreal needleleaf forest, and temperate mixed forest. The purpose was to: (1) develop accurate maps of land cover, based on the MODIS IGBP (International Geosphere-Biosphere Programme) land cover classification scheme; (2) derive continuous surfaces of LAI that capture the mean and variability of the LAI field measurements; and (3) conduct initial MODIS validation exercises to assess the quality of early (i.e., provisional) MODIS products. ETM+ land cover maps varied in overall accuracy from 81% to 95%. The boreal forest was the most spatially complex, had the greatest number of classes, and the lowest accuracy. The intensive agricultural cropland had the simplest spatial structure, the least number of classes, and the highest overall accuracy. At each site, mapped LAI patterns generally followed patterns of land cover across the site. Predicted versus observed LAI indicated a high degree of correspondence between field-based measures and ETM+ predictions of LAI. Direct comparisons of ETM+ land cover maps with Collection 3 MODIS cover maps revealed several important distinctions and similarities. One obvious difference was associated with image/map resolution. ETM+ captured much of the spatial complexity of land cover at the sites. In contrast, the relatively coarse resolution of MODIS did not allow for that level of spatial detail. Over the extent of all sites, the greatest difference was an overprediction by MODIS of evergreen needleleaf forest cover at the boreal forest site, which consisted largely of open shrubland, woody savanna, and savanna. At the agricultural, temperate mixed forest, and prairie grassland sites, ETM+ and MODIS cover estimates were similar. Collection 3 MODIS-based LAI estimates were considerably higher (up to 4 m2 m-2) than those based on ETM+ LAI at each site. There are numerous probable reasons for this, the most important being the algorithms' sensitivity to MODIS reflectance calibration, its use of a prelaunch AVHRR-based land cover map, and its apparent reliance on mainly red and near-IR reflectance. Samples of Collection 4 LAI products were examined and found to consist of significantly improved LAI predictions for KONZ, and to some extent for AGRO, but not for the other two sites. In this study, we demonstrate that MODIS reflectance data are highly correlated with LAI across three study sites, with relationships increasing in strength from 500 to 1000 m spatial resolution, when shortwave-infrared bands are included.

Public Participation GIS: A New Method for Use in National Forest Planning.
About this Resource: In this article we describe and evaluate a public participation geographic information systems (PPGIS) methodology for use in national forest planning in the United States. The Internet-based mapping method collects public landscape values and special places data for input into a national forest planning decision support system. The PPGIS method presupposes that, within their existing statutory framework, national forests should be managed for compatibility with the range of values the public holds for those lands and that inadequate understanding, modeling, and documentation of place-specific forest values can negatively affect public acceptance, viability, and the usefulness of national forest plans. In this article we 1) review previous applications of landscape value mapping methods across a variety of planning applications, 2) describe the participatory, Internet mapping method used in three studies of national forests in Arizona and Oregon in 2006 and 2007, 3) present and evaluate the results to show likely future implementation constraints, and 4) based on lessons learned, describe a recommended PPGIS protocol for national forest planning. The results from the three studies demonstrate that an Internet, participatory mapping method, although not without limitations, can be effective in measuring landscape value and special place data for use in a variety of forest planning processes. Because the protocol expands and in a sense democratizes the agency's public participation process, implementation of the PPGIS protocol across the national forest system can help restore public trust in the agency's forest planning processes and forest management decisions.

Effects of Off-Highway Vehicle Use on the American Marten
About this Resource: Motorized recreation in North American wildlands is increasing, and technological developments in the power and range of vehicles has increased access to high-elevation habitats. The American marten (Martes americana) is vulnerable to this disturbance because martens, like other residents of high-elevation forests, are associated with remote wilderness conditions where the presence of motorized vehicles is a recent phenomenon. We evaluated the effects of vehicles at 2 study sites in California, USA, by comparing marten occupancy rates and probabilities of detection in areas where recreational vehicle use is legal and encouraged (use areas) with wilderness areas where vehicles are prohibited (non-use areas). We sampled vehicle occurrence in nearby use and non-use areas using sound level meters and determined marten occurrence using track and camera stations. We also included 2 secondary measures of potential effects of vehicles on martens: sex ratio and circadian pattern of activity. Martens were ubiquitous in use and non-use areas in both study sites, and there was no effect of vehicle use on marten occupancy or probability of detection. We predicted that females might be less common and martens more nocturnal in use than in nonuse areas, but neither occurred. Martens were exposed to low levels of disturbance in our study sites. We estimated that a marten might be exposed to 0.5 vehicle passes/hour and that this exposure had the greatest effect on ,20% of a typical home range area. Furthermore, vehicle use usually occurred when martens were inactive. We did not measure behavioral, physiological, or demographic responses, so it is possible that vehicles may have effects, alone or in concert with other threats (e.g., timber harvest), that we did not quantify. We encourage additional studies to determine whether other montane species that are year-round residents demonstrate the same response to motorized vehicles.

Soil variability along a nitrogen mineralization and nitrification gradient in a nitrogen-saturated hardwood forest
About this Resource: Some N-saturated watersheds of the Fernow Experimental Forest (FEF), West Virginia, exhibit a high degree of spatial heterogeneity in soil N processing. We used soils from four sites at FEF representing a gradient in net N mineralization and nitrification to consider the causes and consequences of such spatial heterogeneity. We collected soils with extremely high vs. low rates of N processing within each of two watersheds: WS3, treated for 15 yr with (NH4)2SO4, and WS4, untreated reference (control). Mineral soil was analyzed for extractable NH4, NO3, Ca, and Al before and during 28-d incubations at 10, 20, and 30 degrees C after 7, 14, 21, and 28 d. To address the fourth question, we decreased C:N ratios in the soil exhibiting lowest field rates of net N mineralization and no net nitrification (control-low N) by adding glycine and increased C:N ratios in the soil exhibiting highest field rates of net N mineralization and nitrification by adding sucrose. Incubations under controlled conditions supported the N-processing gradient found in the field under in situ conditions in the following order from highest to lowest rates of N mineralization and nitrification: control-high N > N-treated-high N > N-treated-low N > control-low N, the latter exhibiting no net nitrification in the field. Net Ca mineralization increased with net nitrification along the gradient from zero to highest rates. Soil Al appeared to inhibit net nitrification, being lowest in the soil with highest net nitrification and highest in the soil exhibiting no net nitrification. Glycine additions to this latter soil greatly stimulated net N mineralization but failed to initiate net nitrification. Sucrose additions resulted in net immobilization of NH4 and NO3 in soil with highest net N mineralization and nitrification. Results demonstrate that increased nitrification may enhance Ca mobility in N-saturated soils and further demonstrate that substrate quality alone is not necessarily a good predictor of soil N processing.

Assessing rates of forest change and fragmentation in Alabama, USA, using the vegetation change tracker model
About this Resource: Forest change is of great concern for land use decision makers and conservation communities. Quantitative and spatial forest change information is critical for addressing many pressing issues, including global climate change, carbon budgets, and sustainability. In this study, our analysis focuses on the differences in geospatial patterns and their changes between federal forests and nonfederal forests in Alabama over the time period 1987-2005, by interpreting 163 Landsat Thematic Mapper (TM) scenes using a vegetation change tracker (VCT) model. Our analysis revealed that for the most part of 1990s and between 2000 and 2005, Alabama lost about 2% of its forest on an annual basis due to disturbances, but much of the losses were balanced by forest regeneration from previous disturbances. The disturbance maps revealed that federal forests were reasonably well protected, with the fragmentation remaining relatively stable over time. In contrast, nonfederal forests, which are predominant in area share (about 95%), were heavily disturbed, clearly demonstrating decreasing levels of fragmentation during the time period 1987-1993 giving way to a subsequent accelerating fragmentation during the time period 1994-2005. Additionally, the identification of the statistical relationships between forest fragmentation status and forest loss rate and forest net change rate in relation to land ownership implied the distinct differences in forest cutting rate and cutting patterns between federal forests and nonfederal forests. The forest spatial change information derived from the model has provided valuable insights regarding regional forest management practices and disturbance regimes, which are closely associated with regional economics and environmental concerns.

A link between hurricane-induced tree sprouting, high stem density and short canopy in tropical dry forest.
About this Resource: The physiognomy of Caribbean dry forest is shorter, denser and contains a greater proportion of multi-stemmed trees than other neotropical dry forests. Our previous research, conducted after Hurricane Georges in 1998, has shown that dry forest trees sprout near the base following hurricane disturbance, even if the trees have not incurred structural damage. However, for these hurricane-induced sprouts to contribute to the physiognomy of the forest, they must grow and survive. We followed sprout dynamics and stem mortality on 1,407 stems from 1998, after Hurricane Georges, until 2005. The number of surviving sprouts and the proportion of sprouting stems decreased during the 7-year period, but the sprouting rate was still 3-fold higher and the proportion of sprouting stems 5-fold higher than before the hurricane. Mortality of non-sprouting stems (15.4%) was about the same as for sprouting stems (13.9%) after 7 years. The mean length of the dominant sprout surpassed 1.6 m by 2005, with over 13% of the dominant sprouts reaching subcanopy height. Sprout growth and survival varied among species. These results demonstrate that, despite some thinning, hurricane-induced sprouts survive and grow and that the unique physiognomic characteristic of Caribbean dry forests is related to hurricane disturbance.

Relationships between urbanization and the oak resource of the Minneapolis/St. Paul Metropolitan area from 1991 to 1998
About this Resource: Urbanization was associated with loss and transformation of the oak forest in the Twin Cities (Minneapolis and St. Paul) metropolitan area (TCMA) over a recent 7-year interval. Between 1991 and 1998, urbanization increased based on several indicators: population density, area of developed land, and area of impervious surface---total impervious area and area within three classes of increasing degree of imperviousness (protected, affected, and degraded). We quantified relationships between changes in urbanization and changes in several parameters describing the oak forest at the scale of ecological subsection. Increased total and affected impervious area were strongly correlated with decreased area of oak forest when changes of the urbanization indicators and oak were expressed as percentages of the subsection area. Relationships were reversed when changes were expressed as percentages of the 1991 values. Increased population density was strongly correlated with increased loss in numbers and increased isolation of oak patches, but weakly correlated with loss of oak forest area. This is the first study to quantify relationships between changes in urbanization and changes in a specific forest cover type. Our results demonstrate complexities of urbanization impacts on a metropolitan forest resource, and highlight the importance of selected variables, spatial and temporal scales, and expressions of change when quantifying these relationships.

Effects of Natural Barriers and Habitat on the Western Spread of Raccoon Rabies in Alabama.
About this Resource: Although domestic animal transmission of rabies has largely been mitigated, the disease remains a concern in both Europe and North America where wildlife transmission has caused epizootics. Raccoon (Procyon lotor) rabies was established in Alabama, USA, in 1975, primarily in the southeastern corner of the state. However, with the exception of isolated events, rabies has not continued to spread westward across the Alabama River. We monitored movements of 100 radiocollared raccoons on 2 sites within hardwood and agriculture habitats in a rabies enzootic area east of the Alabama River, in managed pine habitat area west of the river where rabies sporadically occurs, and in a mixed pine hardwood area outside of the known rabies enzootic area to determine if raccoon movements and habitat use in certain habitat types and the presence of a river may serve as natural barriers preventing the western spread of rabies in Alabama. We also examined raccoon contact rates to determine if they influence disease transmission through static and dynamic interactions. Raccoons in mixed pine-hardwood forest habitats had smaller home ranges and less overlap of ranges compared to the other 3 habitats. However, static interactions between habitats in the use of overlap areas did not differ (F11,129 = 1.63, P = 0.09). Rabies antibody titers were highest in the managed pine habitat (28%) even prior to oral vaccine bait distributions in spring of 2004 and 2005. Biomarker data from radiocollared and additional raccoons captured after the bait distribution west of the Alabama River demonstrated a low efficacy of the vaccine reaching the small southern raccoons. The combination of the river as a partial barrier, the high percentage of pine forested habitat west of the river, and limited spatial movements of raccoons within these forested habitats appears to have reduced the likelihood of rabies establishing west of the river. Understanding different host-habitat-disease systems is important for successful management of diseases. Based on our results, we recommend that the oral vaccine program continue to use the Alabama River as a partial barrier and baiting be concentrated in the fragmented bottomland hardwood forests and around larger bodies of water where raccoon densities are highest. Success of baiting strategies designed to take advantage of northern raccoon dynamics and habitat use may not be applicable to southern populations.

Associations of forest bird species richness with housing and landscape patterns across the USA
About this Resource: In the United States, housing density has substantially increased in and adjacent to forests. Our goal in this study was to identify how housing density and human populations are associated with avian diversity. We compared these associations to those between landscape pattern and avian diversity, and we examined how these associations vary across the conterminous forested United States. Using data from the North American Breeding Bird Survey, the U.S. Census, and the National Land Cover Database, we focused on forest and woodland bird communities and conducted our analysis at multiple levels of model specificity, first using a coarse-thematic resolution (basic models), then using a larger number of fine-thematic resolution variables (refined models). We found that housing development was associated with forest bird species richness in all forested ecoregions of the conterminous United States. However, there were important differences among ecoregions. In the basic models, housing density accounted for <5% of variance in avian species richness. In refined models, 85% of models included housing density and/or residential land cover as significant variables. The strongest guild response was demonstrated in the Adirondack-New England ecoregion, where 29% of variation in richness of the permanent resident guild was associated with housing density. Model improvements due to regional stratification were most pronounced for cavity nesters and short-distance migrants, suggesting that these guilds may be especially sensitive to regional processes. The varying patterns of association between avian richness and attributes associated with landscape structure suggested that landscape context was an important mediating factor affecting how biodiversity responds to landscape changes. Our analysis suggested that simple, broadly applicable, land use recommendations cannot be derived from our results. Rather, anticipating future avian response to land use intensification (or reversion to native vegetation) has to be conditioned on the current landscape context and the species group of interest. Our results show that housing density and residential land cover were significant predictors of forest bird species richness, and their prediction strengths are likely to increase as development continues.

The relative uptake of Ca and Sr into tree foliage using a whole-watershed calcium addition
About this Resource: The use of strontium isotopes and ratios of alkaline earth elements (i.e., ⁸⁷Sr/⁸⁶Sr and Ca/Sr) to trace Ca sources to plants has become common in ecosystem studies. Here we examine the relative uptake of Ca and Sr in trees and subsequent accumulation in foliage. Using a whole-watershed Ca addition experiment at the Hubbard Brook Experimental Forest in N.H., we measured the uptake of Ca relative to Sr in foliage and roots of sugar maple (Acer saccharum), yellow birch (Betula alleghaniensis), American beech (Fagus grandifolia), and red spruce (Picea rubens). Vegetation was analyzed for Ca and Sr concentrations and the ⁸⁷Sr/⁸⁶Sr ratio. A comparison of the Ca/Sr ratio in the vegetation and the Ca/Sr ratio of the applied mineral allows for the calculation of a discrimination factor, which defines whether Ca and Sr are incorporated and allocated in the same ratio as that which is available. A discrimination factor greater than unity indicates preferential uptake of Ca over Sr; a factor less than unity reflects preferential uptake of Sr over Ca. We demonstrate that sugar maple (SM) and yellow birch (YB) have similar and small discrimination factors (1.14 ± 0.12,1σ and 1.16 ± 0.09,1σ) in foliage formation and discrimination factors of less than 1 in root formation (0.55-0.70). Uptake into beech suggests a larger discrimination factor (1.9 ± 1.2) in foliage but a similar root discrimination factor to SM and YB (0.66 ± 0.06,1σ). Incorporation into spruce foliage occurs at a much slower rate than in these other tree species and precludes evaluation of Ca and Sr discrimination in spruce foliage at this time. Understanding the degree to which Ca is fractionated from Sr in different species allows for refinement in the use of ⁸⁷Sr/⁸⁶Sr and Ca/Sr ratios to trace Ca sources to foliage. Methods from this study can be applied to natural environments in which various soil cation pools have different ⁸⁷Sr/⁸⁶Sr and Ca/Sr ratios. The results reported herein have implications for re-evaluating Ca sources and fluxes in forest ecosystems.

Radiation use efficiency in adjacent hardwood and pine forests in the southern Appalachians
About this Resource: The efficiency with which trees convert photosynthetically active radiation (PAR) to biomass has been shown to be consistent within stands of an individual species, which is useful for estimating biomass production and carbon accumulation. However, radiation use efficiency (ε) has rarely been measured in mixed-species forests, and it is unclear how species diversity may affect the consistency of ε, particularly across environmental gradients. We compared aboveground net primary productivity (ANPP), intercepted photosynthetically active solar radiation (IPAR), and radiation use efficiency (ε =ANPP/IPAR) between a mixed deciduous forest and a 50-year-old white pine (Pinus strobus L.) plantation in the southern Appalachian Mountains. Average ANPP was similar in the deciduous forest (11.5Mgha⁻¹ y⁻¹) and pine plantation (10.2Mgha⁻¹ y⁻¹), while ε was significantly greater in the deciduous forest (1.25gMJ⁻¹) than in the white pine plantation (0.63gMJ⁻¹). Our results demonstrate that late-secondary hardwood forests can attain similar ANPP as mature P. strobus plantations in the southern Appalachians, despite substantially less annual IPAR and mineral-nitrogen availability, suggesting greater resource-use efficiency and potential for long-term carbon accumulation in biomass. Along a 260m elevation gradient within each forest there was not significant variation in ε. Radiation use efficiency may be stable for specific forest types across a range of environmental conditions in the southern Appalachian Mountains, and thus useful for generating estimates of ANPP at the scale of individual watersheds.

Seasonal and spatial distributions of adult screwworms (Diptera: Calliphoridae) in the Panama Canal area, Republic of Panama.
About this Resource: The distribution of screwworms, Cochliomyia hominivorax, (Coquerel) was studied in a seasonally moist lowland tropical forest in the Republic of Panama using a combination of field collections and satellite imagery. We found that different forest types could be distinguished and mapped using remotely sensed data. To determine the temporal and spatial distribution of flies, we collected flies coming to rotted liver at 82 sites in ten vegetation types (open areas, edge forest, dry scrub forest, forest successional stage 1, forest successional stage 2, forest successional stage 3, forest successional stage 4, forest successional stage 5, mature forests, palm swamp forest, and forest along streams) over three seasons (dry, transitional, wet). Nine of the vegetation types (excluding dry scrub forest) were identified and mapped using SPOT XS and Landsat 5 TM satellite data. Screwworm flies were most abundant during the transition from wet to dry season. Fly numbers were consistently higher in forest habitats, particularly those with trees 20-30 m in height and a fairly open canopy composed of many deciduous species that shed their leaves during the dry season. Screwworm numbers were also high in palm swamp forest, edge forest, and mature growth forest. Traps sampled in open areas had fewer flies and were unrelated to proximity to cattle. Females accounted for 88% of the total fly counts. This study further substantiates the importance of forests in the ecology and behavior of screwworm flies and demonstrates that remotely sensed data can be used to construct the spatial distribution of these flies in a tropical landscape. We discuss implications of this information to the screwworm eradication program.

Distinguishing stressors acting on land bird communities in an urbanizing environment.
About this Resource: Urbanization has profound influences on ecological communities, but our understanding of causal mechanisms is limited by a lack of attention to its component stressors. Published research suggests that at landscape scales, habitat loss and fragmentation are the major drivers of community change, whereas at local scales, human activity and vegetation management are the primary stressors. Little research has focused on whether urbanization stressors may supplant natural factors as dominant forces structuring communities. We used model selection to determine the relative importance of urban development, human activity, local and landscape vegetation, topography, and geographical location in explaining land bird species richness, abundance, and dominance. We analyzed the entire community and groups of species based on ecological characteristics, using data collected in remnant forests along a gradient of urban development in the Lake Tahoe basin, California and Nevada, USA. Urbanization stressors were consistently among the principal forces structuring the land bird community. Strikingly, disturbance from human activity was the most important factor for richness in many cases, surpassing even habitat loss from development. Landscape-scale factors were consistently more important than local-scale factors for abundance. In demonstrating considerable changes in land bird community structure, our results suggest that ecosystem function in urban areas may be severely compromised. Such changes compel local- and landscape-scale management, focused research, and long-term monitoring to retain biodiversity in urban areas to the extent possible. Keywords

Linking flux network measurements to continental scale simulations: ecosystem carbon dioxide exchange capacity under non-water-stressed conditions
About this Resource: This paper examines long-term eddy covariance data from 18 European and 17 North American and Asian forest, wetland, tundra, grassland, and cropland sites under non-water-stressed conditions with an empirical rectangular hyperbolic light response model and a single layer two light-class carboxylase-based model. Relationships according to ecosystem functional type are demonstrated between empirical and physiological parameters, suggesting linkages between easily estimated parameters and those with greater potential for process interpretation. Relatively sparse documentation of leaf area index dynamics at flux tower sites is found to be a major difficulty in model inversion and flux interpretation. Therefore, a simplification of the physiological model is carried out for a subset of European network sites with extensive ancillary data. The results from these selected sites are used to derive a new parameter and means for comparing empirical and physiologically based methods across all sites, regardless of ancillary data. The results from the European analysis are then compared with results from the other Northern Hemisphere sites and similar relationships for the simplified process-based parameter were found to hold for European, North American, and Asian temperate and boreal climate zones. This parameter is useful for bridging between flux network observations and continental scale spatial simulations of vegetation/atmosphere carbon dioxide exchange.

Snag density varies with intensity of timber harvest and human access
About this Resource: Many species of vertebrates depend on snags (standing dead trees) for persistence, and limited research suggests that snag density is lower in areas of intensive timber harvest and increased human access. While intensive timber harvest is one source of potential snag loss, ease of human access to forest stands may also facilitate loss via firewood cutting of snags. Accordingly, we hypothesized that density of snags (number of snags/ha) would decline in forest stands with increasing intensity of timber harvest and increasing ease of human access. We tested our hypothesis by sampling stands under varying levels of timber harvest and access on National Forest land in the northwestern United States. Stands with no history of timber harvest had 3 times the density of snags as stands selectively harvested, and 19 times the density as stands having undergone complete harvest. Stands not adjacent to roads had almost 3 times the density of snags as stands adjacent to roads. Unharvested stands adjacent to non-federal lands and closer to towns had lower snag density, as did stands with flat terrain in relation to nearest road. Our findings demonstrate that timber harvest and human access can have substantial effects on snag density. Meeting snag objectives for wildlife will require careful planning and effective mitigations as part of management of timber harvest and human access.

Modelling dwarf mistletoe at three scales: life history, ballistics and contagion
About this Resource: The epidemiology of dwarf mistletoe (Arceuthobium) is simulated for the reproduction, dispersal, and spatial patterns of these plant pathogens on conifer trees. A conceptual model for mistletoe spread and intensification is coded as sets of related subprograms that link to either of two individual-tree growth models (FVS and TASS) used by managers to develop silvicultural and land management plans. This dwarf mistletoe model is based on knowledge of mistletoe biology and forest practices acquired through a series of workshops, programming exercises, and continuing research and development. Key components of mistletoe epidemiology are identified as life history, ballistics, and contagion. An infestation is quantified at the tree-level by a standard measure of mistletoe intensity, the dwarf mistletoe rating (DMR). Life history describes the progression of mistletoe populations from new infections to seed-producing plants and includes biocontrol and mortality of the mistletoe. The model tracks mistletoe populations as changes in DMR rather than individual plants. Life history is represented as changes in pools for various developmental stages; and rates of change are modified by time, light, and other environmental factors (including hyperparasites). Dwarf mistletoes disperse by explosive discharge of small seeds followed by ballistic flight that displaces seeds horizontally to a maximum distance of about 14 m. The model represents dispersal as probabilistic, spatially explicit, ballistic trajectories for each host tree in a simulated stand. The spacing of trees and mistletoe within infested stands exhibits a range of patterns as regular, random, or clumped; the rates of spread to new hosts and intensification within infested hosts are influenced by crown and canopy distributions derived from descriptors of stem clumping and mistletoe contagion. Spatial arrangements of trees in the model are determined from stand-level statistics that characterize groups of trees at the scale of a 14 m radius neighborhood, the maximum distance for ballistic dispersal. The number of trees in a simulated neighborhood is a function of the variance to mean ratio for tree density in the stand. The autocorrelation of trees of more similar DMR is used to simulate aggregation of infected trees into infestation patches. Model behavior for sensitivity to key relationships and fit to observed stands is demonstrated using data for a dense western hemlock stand and two initially similar, open-canopy ponderosa pine stands either treated for mistletoe or left untreated. The model provides a practical tool for assessing the long-term, cumulative effects of disease and management in mistletoe-infested stands.

Transmission of Phytophthora ramorum in mixed-evergreen forest in California.
About this Resource: During 2001 to 2003, the transmission biology of Phytophthora ramorum, the causal agent of sudden oak death, was studied in mixed-evergreen forest, a common forest type in northern, coastal California. Investigation of the sources of spore production focused on coast live oak (Quercus agrifolia) and bay laurel (Umbellularia californica), dominant hosts that comprised 39.7 and 46.2% of the individuals at the study site, respectively. All tests for inoculum production from the surface of infected coast live oak bark or exudates from cankers were negative. In contrast, sporangia and chlamydospores were produced on the surface of infected bay laurel leaves. Mean number of zoospores produced from infected bay laurel leaves under natural field conditions during rainstorms was 1,173.0 +/- SE 301.48, and ranged as high as 5,200 spores/leaf. P. ramorum was recovered from rainwater, soil, litter, and streamwater during the mid- to late rainy season in all 3 years of the study. P. ramorum was not recovered from sporadic summer rains or soil and litter during the hot, dry summer months. Concentrations of inoculum in rainwater varied significantly from year to year and increased as the rainy season progressed for the two complete seasons that were studied. Potential dispersal distances were investigated for rainwater, soil, and streamwater. In rainwater, inoculum moved 5 and 10 m from the inoculum source. For soil, transmission of inoculum was demonstrated from infested soil to bay laurel green leaf litter, and from bay laurel green leaf litter to aerial leaves of bay laurel seedlings. One-third to one-half of the hikers tested at the study site during the rainy season also were carrying infested soil on their shoes. In streamwater, P. ramorum was recovered from an unforested site in pasture approximately equal to 1 km downstream of forest with inoculum sources. In total, these studies provide details on the production and spread of P. ramorum inoculum in mixed-evergreen forest to aid forecasting and managing disease transmission of this environmentally destructive pathogen.

Response of sugar maple to calcium addition to northern hardwood forest. [2006 Aug., v. 87, no. 8, p. 2131.]
About this Resource: Watershed budget studies at the Hubbard Brook Experimental Forest (HBEF), New Hampshire, USA, have demonstrated high calcium depletion of soil during the 20th century due, in part, to acid deposition. Over the past 25 years, tree growth (especially for sugar maple) has declined on the experimental watersheds at the HBEF. In October 1999, 0.85 Mg Ca/ha was added to Watershed 1 (W1) at the HBEF in the form of wollastonite (CaSiO3), a treatment that, by summer 2002, had raised the pH in the Oie horizon from 3.8 to 5.0 and, in the Oa horizon, from 3.9 to 4.2. We measured the response of sugar maple to the calcium fertilization treatment on W1. Foliar calcium concentration of canopy sugar maples in W1 increased markedly beginning the second year after treatment, and foliar manganese declined in years four and five. By 2005, the crown condition of sugar maple was much healthier in the treated watershed as compared with the untreated reference watershed (W6). Following high seed production in 2000 and 2002, the density of sugar maple seedlings increased significantly on W1 in comparison with W6 in 2001 and 2003. Survivorship of the 2003 cohort through July 2005 was much higher on W1 (36.6%) than W6 (10.2%). In 2003, sugar maple germinants on W1 were approximately 50% larger than those in reference plots, and foliar chlorophyll concentrations were significantly greater (0.27 g/m2 vs. 0.23 g/m2 leaf area). Foliage and fine-root calcium concentrations were roughly twice as high, and manganese concentrations twice as low in the treated than the reference seedlings in 2003 and 2004. Mycorrhizal colonization of seedlings was also much greater in the treated (22.4% of root length) than the reference sites (4.4%). A similar, though less dramatic, difference was observed for mycorrhizal colonization of mature sugar maples (56% vs. 35%). These results reinforce and extend other regional observations that sugar maple decline in the northeastern United States and southern Canada is caused in part by anthropogenic effects on soil calcium status, but the causal interactions among inorganic nutrition, physiological stress, mycorrhizal colonization, and seedling growth and health remain to be established.

Increases in nitrogen uptake rather than nitrogen-use efficiency support higher rates of temperate forest productivity under elevated CO₂.
About this Resource: Forest ecosystems are important sinks for rising concentrations of atmospheric CO₂. In previous research, we showed that net primary production (NPP) increased by 23 ± 2% when four experimental forests were grown under atmospheric concentrations of CO₂ predicted for the latter half of this century. Because nitrogen (N) availability commonly limits forest productivity, some combination of increased N uptake from the soil and more efficient use of the N already assimilated by trees is necessary to sustain the high rates of forest NPP under free-air CO₂ enrichment (FACE). In this study, experimental evidence demonstrates that the uptake of N increased under elevated CO₂ at the Rhinelander, Duke, and Oak Ridge National Laboratory FACE sites, yet fertilization studies at the Duke and Oak Ridge National Laboratory FACE sites showed that tree growth and forest NPP were strongly limited by N availability. By contrast, nitrogen-use efficiency increased under elevated CO₂ at the POP-EUROFACE site, where fertilization studies showed that N was not limiting to tree growth. Some combination of increasing fine root production, increased rates of soil organic matter decomposition, and increased allocation of carbon (C) to mycorrhizal fungi is likely to account for greater N uptake under elevated CO₂. Regardless of the specific mechanism, this analysis shows that the larger quantities of C entering the below-ground system under elevated CO₂ result in greater N uptake, even in N-limited ecosystems. Biogeochemical models must be reformulated to allow C transfers below ground that result in additional N uptake under elevated CO₂.

Accuracy of Regeneration Surveys in New England Northern Hardwoods
About this Resource: Four 5-ac demonstration harvests were initiated in 1951 on the Bartlett Experimental Forest, New Hampshire: light selection, moderate selection, diameter limit, and liquidation. In 1952 and 1959, regeneration surveys were conducted that measured several different attributes of the seedlings and saplings in the cutover stands. In 2005, the stands were remeasured to determine the relationships of the various regeneration measures to current species composition of the pole-timber portion of the stands. Although predictions were somewhat variable and imperfect, the best measures for shade-tolerant species were those that took account of the sapling layer, and measures based on the dominant stem per small plot were best for less-tolerant species. Combining both attributes, these results suggest that the best approach would be a small-plot survey (milacre or slightly larger) that simply records the dominant stem per plot including stems up through the sapling size classes (less than 4.5-in. dbh). This could be taken before harvest, to predict the effects of a light partial cut, or 5-7 years after harvest, to predict future species composition after any harvest intensity.

Forest development following mudflow deposition, Mount St. Helens, Washington
About this Resource: Volcanic mudflows are locally important disturbance agents in the Pacific Northwest rarely studied within the context of forest succession. We describe 18 years (1981-1999) of forest development on the Muddy River mudflow deposit following the 1980 eruption of Mount St. Helens using permanent plot data collected along two transects traversing the Cedar Flats river terrace. We analyze changing forest structure over the study period and compare results with mudflow deposition using correlation and pairwise comparisons, as well as ordination (detrended correspondence analysis) and cluster analysis. Our results show a statistically significant relationship between mudflow deposition and forest change. Following mudflow deposition, the site consisted of patches of high tree mortality caused by deep mudflow deposits in abandoned river channels as well as patches of accelerated regeneration of surviving understory trees in areas of more shallow mudflow deposition and partial overstory mortality. Mudflow deposition at the site initiated multiple stages of stand development with (1) early-colonizing red alder (Alnus rubra Bong.) dominating deep deposition sites with fewer surviving trees, (2) gap recruitment and establishment by western hemlock (Tsuga heterophylla (Raf.) Sarg.) and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) on intermediate to deep deposition sites with more postburial surviving trees, and (3) late-seral conditions and accelerated succession on shallow burial sites, where tree mortality was low. The initiation of differing succession trajectories, as well as variability in the extent and timing of tree mortality following mudflow deposition, demonstrates a dynamic response to disturbance in relation to small-scale gradients of mudflow deposition.

Regional patterns in foliar 15N across a gradient of nitrogen deposition in the northeastern US
About this Resource: Recent studies have demonstrated that natural abundance 15N can be a useful tool for assessing nitrogen saturation, because as nitrification and nitrate loss increase, δ15N of foliage and soil also increases. We measured foliar δ15N at 11 high-elevation spruce-fir stands along an N deposition gradient in 1987-1988 and at seven paired northern hardwood and spruce-fir stands in 1999. In 1999, foliar δ15N increased from -5.2 to -0.7[per thousand] with increasing N deposition from Maine to NY. Foliar δ15N decreased between 1987-1988 and 1999, while foliar %N increased and foliar C:N decreased at most sites. Foliar δ15N was strongly correlated with N deposition, and was also positively correlated with net nitrification potential and negatively correlated with soil C:N ratio. Although the increase in foliar %N is consistent with a progression towards N saturation, other results of this study suggest that, in 1999, these stands were further from N saturation than in 1987-1988. Foliar δ15N increased with increasing N deposition from Maine to NY, but decreased between 1987-1988 and 1999

Invasive plants transform the three-dimensional structure of rain forests
About this Resource: Biological invasions contribute to global environmental change, but the dynamics and consequences of most invasions are difficult to assess at regional scales. We deployed an airborne remote sensing system that mapped the location and impacts of five highly invasive plant species across 221,875 ha of Hawaiian ecosystems, identifying four distinct ways that these species transform the three-dimensional (3D) structure of native rain forests. In lowland to montane forests, three invasive tree species replace native midcanopy and understory plants, whereas one understory invader excludes native species at the ground level. A fifth invasive nitrogen-fixing tree, in combination with a midcanopy alien tree, replaces native plants at all canopy levels in lowland forests. We conclude that this diverse array of alien plant species, each representing a different growth form or functional type, is changing the fundamental 3D structure of native Hawaiian rain forests. Our work also demonstrates how an airborne mapping strategy can identify and track the spread of certain invasive plant species, determine ecological consequences of their proliferation, and provide detailed geographic information to conservation and management efforts.

Drought-induced nitrous oxide flux dynamics in an enclosed tropical forest
About this Resource: El Niño-La Niña cycles strongly influence dry and wet seasons in the tropics and consequently nitrous oxide (N2O) emissions from tropical rainforest soils. We monitored whole-system and soil chamber N2O fluxes during 5-month-long droughts in the Biosphere 2 tropical forest to determine how rainfall changes N2O production. A consistent pattern of N2O flux changes during drought and subsequent wetting emerged from our experiments. Soil surface drying during the first days of drought, presumably increased gas transport out of the soil, which increased N2O fluxes. Subsequent drying caused an exponential decrease in whole-system (4.0±0.1% day-1) and soil chamber N2O flux (8.9±0.8% day-1; south chamber; and 13.7±1.1% day-1; north chamber), which was highly correlated with soil moisture content. Soil air N2O concentration ([N2O]) and flux measurements revealed that surface N2O production persisted during drought. The first rainfall after drought triggered a N2O pulse, which amounted to 25% of drought-associated reduction in N2O flux and 1.3±0.4% of annual N2O emissions. Physical displacement of soil air by water and soil chemistry changes during drought could not account for the observed N2O pulse. We contend that osmotic stress on the microbial biomass must have supplied the N source for pulse N2O, which was produced at the litter-soil interface. After the pulse, N2O fluxes were consistently 90% of predrought values. Nitrate change rate, nutrient, [N2O], and flux analyses suggested that nitrifiers dominated N2O production during the pulse and denitrifiers during wet conditions. N2O flux measurements in Biosphere 2, especially during the N2O pulse, demonstrate that large-scale integration methods, such as flux towers, are essential for improving ecosystem N2O flux estimates.

Conversion of deciduous forest to silvopasture produces soil properties indicative of rapid transition to improved pasture
About this Resource: Differences in soil properties between forests and pastures have been well documented in the literature, especially under coniferous forests. However, since nearly all of these reports have been time-point comparisons, utilizing long-term paired-sites, properties of transitional states and time of their appearance can only be inferred at present. In this study, a deciduous forest ecosystem was converted to a silvopasture ecosystem by tree thinning, fertilization, and sheep incorporation of seed and forest litter. After 2 years, topsoil (0-15 cm) physico-chemical properties, particularly P fractions, and phosphatases were monitored over the growing season in these ecosystems, and a nearby pasture ecosystem. Initially, before spring vegetative growth, differences were found for pH, exchangeable cations and soil moisture, most of which could be explained by management history. Compared to forest, organic-C (Co) and organic-N (No) concentrations were reduced in silvopasture by 17 and 9%, respectively, indicative of substantial litter decomposition. Most values for all these physico-chemical properties for silvopasture were intermediate between forest and pasture, and generally remained so throughout the growing season. Initial total P (TPt), organic-P (TPo) and inorganic-P (TPi) concentrations were generally as anticipated for the forest and pasture. Silvopasture, however, had 36 and 23% greater TPo than forest and pasture, respectively, presumably due to fertilizer-P immobilization induced by incorporation of forest litter. Total P components remained essentially constant over the growing season in all ecosystems, with the exception of pasture, likely due to high forage TPi uptake. Bray I-extractable-organic-P (BrPo) and bicarbonate-extractable-organic-P (BiPo) concentrations, although consistently highest in the forest and silvopasture soils, were not reflective of the increase in TPo under silvopasture. Acid phosphatase (PMEac) activities were highest in spring in all the ecosystems, then gradually declined to typically 25-50% initial activities. Alkaline phosphatase (PMEal) activities showed a broadly-similar pattern, with exception of forest and silvopasture soils, which exhibited low activities throughout the season. For the entire data set, PMEac and PMEal activities were poorly correlated with TPi, BrPi, and BiPi. These results demonstrate that conversion of forest to silvopasture results in soil changes indicative of its rapid transition to pasture and that an increased Po reservoir results that should be taken into account in fertilizer-P recommendations for temperate silvopastures.

The responses of understorey birds to forest fragmentation, logging and wildfires: An Amazonian synthesis
About this Resource: We combine mist-net data from 24 disturbance treatments taken from seven studies on the responses of understorey Amazonian birds to selective logging, single and recurrent wildfires, and habitat fragmentation. The different disturbance treatments had distinct effects on avian guild structure, and fire disturbance and the isolation of forest patches resulted in bird communities that were most divergent from those in continuous, undisturbed forest in terms of their species composition. Although low-intensity logging treatments had the least noticeable effects, the composition of understorey birds was still markedly different from the composition in undisturbed forest. This analysis demonstrates the importance of preventing habitat fragmentation and the spread of fires in humid tropical forests, and highlights the need for more research to determine the long-term suitability of large areas of degraded forest for forest birds.

Enzyme activities as affected by soil properties and land use in a tropical watershed
About this Resource: Enzyme activities play key roles in the biochemical functioning of soils, including soil organic matter formation and degradation, nutrient cycling, and decomposition of xenobiotics. Knowledge of enzyme activities can be used to describe changes in soil quality due to land use management and for understanding soil ecosystem functioning. In this study, we report the activities of the glycosidases (β-glucosidase, α-galactosidase, and β-glucosaminidase), acid phosphatase, and arylsulfatase, involved in C (C and N for β-glucosaminidase), P, and S cycling, respectively, as affected by soil order and land use within a watershed in north-central Puerto Rico (Caribbean). Representative surface soil (0-15 cm) samples were taken from 84.6% of the total land area (45,067 ha) of the watershed using a completely randomized design. The activity of α-galactosidase was greater in soils classified as Oxisols than in soils classified as Ultisols and Inceptisols, and it was not affected by land use. The activity of β-glucosidase was greater in Oxisols compared to the Inceptisols and Ultisols, and it showed this response according to land use: pasture > forest > agriculture. The activity of β-glucosaminidase was higher in Oxisols than the other soil orders, and it was higher under pasture compared to forest and agriculture. Acid phosphatase and arylsulfatase activities were greater in Oxisols and Ultisols than in Inceptisols, and they decreased in this order due to land use: forest = pasture > agriculture. As a group, β-glucosaminidase, β-glucosidase, and acid phosphatase activities separated the sites under forest and pasture from those under agriculture in a three-dimensional plot. Thus, enzyme activities in Inceptisols under agriculture could be increased to levels comparable to other soil orders with conservative practices similar to those under pasture and secondary forest growth. Our findings demonstrate that within this watershed, acid and low fertility soils such as Oxisols and Ultisols have in general higher enzyme activities than less weathered tropical soils of the order Inceptisols, probably due to their higher organic matter content and finer texture; and that the activities of these enzymes respond to management with agricultural practices decreasing key soil biochemical reactions of soil functioning.

A non-native invasive grass increases soil carbon flux in a Hawaiian tropical dry forest
About this Resource: Non-native plants are invading terrestrial ecosystems across the globe, yet little is known about how invasions impact carbon (C) cycling or how these impacts will be influenced by climate change. We quantified the effect of a non-native C₄ grass invasion on soil C pools and fluxes in a Hawaiian tropical dry forest over 2 years in which annual precipitation was average (Year 1) and ~60% higher than average (Year 2). Work was conducted in a series of forested plots where the grass understory was completely removed (removal plots) or left intact (grass plots) for 3 years before experiment initiation. We hypothesized that grass invasion would: (i) not change total soil C pools, (ii) increase the flux of C into and out of soils, and (iii) increase the sensitivity of soil C flux to variability in precipitation. In grass plots, grasses accounted for 25-34% of litter layer C and ~70% of fine root C. However, no differences were observed between treatments in the size of any soil C pools. Moreover, grass-derived C constituted a negligible fraction of the large mineral soil C pool (< 3%) despite being present in the system for >=50 years. Tree litterfall was ~45% lower in grass plots, but grass-derived litterfall more than compensated for this reduction in both years. Annual cumulative soil-surface CO₂ efflux (Rsoil) was ~40% higher in grass plots in both years, and increased in both treatments by ~36% in the wetter Year 2. Despite minimal grass-derived mineral soil C, > 75% of Rsoil in grass plots was of C₄ (i.e. grass) origin. These results demonstrate that grass invasion in forest ecosystems can increase the flux of C into and out of soils without changing total C pools, at least over the short term and as long as the native tree canopy remains intact, and that invasion-mediated changes in belowground C cycling are sensitive to precipitation.

Nitrogen drives the growth of secondary forests in the Amazon: what analogies with temperate and boreal forests?
About this Resource: Nitrogen drives the growth of secondary forests in the Amazon: what analogies with temperate and boreal forests? A comment is made on a recent paper published on Nature (Davidson et al. 2007), in which the authors demonstrate that in the young secondary forests in the Amazon a conservative nitrogen cycle prevails and nitrogen is a key factor driving forest growth. Analogies are also discussed with recent findings on the role of nitrogen deposition on the carbon balance of temperate and boreal forests (Magnani et al. 2007).

PROSPECTS FOR CONTINGENT VALUATION: LESSONS FROM THE SOUTH-EAST FORESTS
About this Resource: The Contingent Valuation Method (CVM) has been strongly criticised in Australia following two prominent applications. The aims in this paper are to review these criticisms and to demonstrate how, through an application of the method, these potential problems were addressed. The results of the application - a valuation of the conservation benefits of the National Estate forests of Southeastern Australia - are presented. A key feature of the application was the use of focus group testing in the questionnaire design phase. Finally, an assessment is made of the future prospects for the use of the CVM in Australia.

A Simple Algorithm for Large-Scale Mapping of Evergreen Forests in Tropical America, Africa and Asia
About this Resource: The areal extent and spatial distribution of evergreen forests in the tropical zones are important for the study of climate, carbon cycle and biodiversity. However, frequent cloud cover in the tropical regions makes mapping evergreen forests a challenging task. In this study we developed a simple and novel mapping algorithm that is based on the temporal profile analysis of Land Surface Water Index (LSWI), which is calculated as a normalized ratio between near infrared and shortwave infrared spectral bands. The 8-day composites of MODIS Land Surface Reflectance data (MOD09A1) in 2001 at 500-m spatial resolution were used to calculate LSWI. The LSWI-based mapping algorithm was applied to map evergreen forests in tropical Africa, America and Asia (30°N–30°S). The resultant maps of evergreen forests in the tropical zone in 2001, as estimated by the LSWI-based algorithm, are compared to the three global forest datasets [FAO FRA 2000, GLC2000 and the standard MODIS Land Cover Product (MOD12Q1) produced by the MODIS Land Science Team] that are developed through complex algorithms and processes. The inter-comparison of the four datasets shows that the area estimate of evergreen forest from the LSWI-based algorithm fall within the range of forest area estimates from the FAO FRA 2000, GLC2000 and MOD12Q1 at a country level. The area and spatial distribution of evergreen forests from the LSWI-based algorithm is to a large degree similar to those of the MOD12Q1 produced by complex mapping algorithms. The results from this study demonstrate the potential of the LSWI-based mapping algorithm for large-scale mapping of evergreen forests in the tropical zone at moderate spatial resolution.

Greater Flagstaff Forests Partnership
About this Resource: The Greater Flagstaff Forests Partnership is an alliance of 27 environmental and governmental organizations dedicated to researching and demonstrating approaches to forest ecosystem restoration in the ponderosa pine forests surrounding Flagstaff, Arizona. The site contains organizational information such as key elements, staff, annual plans, and structure of the organization. Also found on the site are sections about the restoration projects, monitoring efforts, events, southwestern ponderosa pine forests, and links to other sites.

Tropical Forest Foundation
About this Resource: The TFF is dedicated to the conservation of tropical forests through sustainable forestry. The primary focus of the Tropical Forest Foundation is to demonstrate and teach sustainable forest management through Reduced-impact Logging. This website offers users information about the Foundation as well as publications such as newsletters, bulletins, and other reports. The site also gives information about how the industry can help, Reduced-impact Logging, forestry in the future, and their sponsors.

Weak basis for &#8220;systemic&#8221; silviculture
About this Resource: An analysis is presented of the ecological basis of the so-called &#8220;selvicoltura sistemica&#8221; (systemic silviculture). Systemic silviculture implies an &#8220;a-structured forest&#8221;: the meaning of this particular condition is discussed in the paper, exploring the different possible interpretations and thus demonstrating that an &#8220;a-structured&#8221; forest can not be observed in nature. The silvicultural method proposed therefore seems to have a fragile ecological basis moving it away from a close-to-nature forest management approach, which is currently believed to be the most promising one for achieving forests that provide multiple goods and services.

Fire history in coast redwood forests of the Mendocino Coast, California
About this Resource: We reconstructed fire history in old-growth coast redwood (Sequoia sempervirens) stands along an ocean-to-inland gradient in Jackson Demonstration State Forest on the Mendocino Coast in northern California, USA. Fire history was reconstructed for the past two to four centuries using fire scars recorded in tree rings. Surface fires were frequent disturbances in all stands prior to the early twentieth century. Composite mean fire-free intervals aggregated within stands varied from 6 to 20 years, and point mean fire-free intervals averaged within trees varied from 9 to 20 years. Fires ceased in the early 20th century coincident with the advent of organized fire suppression efforts beginning in the 1930s. Fire frequency did not vary significantly along the ocean-inland gradient. Although several of the inland stands tended to record shorter intervals between fires, there was high variability among sites. These and analogous fire-scar data from other studies across the range of coast redwood forests suggest that fire frequencies have been underestimated in some past assessments. A principal reason is that fire-scar records on coast redwood trees are difficult to locate because of inadequate preservation compared to other species that experienced surface fires. Cessation of surface fires has resulted in shifts in fuel and forest structure over recent decades, and the fire history reconstructed by this study provides both guidelines and justification for ecological restoration efforts in coast redwood forests of this region.

Effect of Ecological Aspects on the Quantitative Variables of Mixed Broadleaf Forests Using Multivariate Statistical Method
About this Resource: This research was performed on the commercial forests of the western Caspian region, Shafa-Rud basin, to investigate firstly the effect of ecological aspects (northern and southern) on the quantitative variables of mixed broadleaf forests using a multivariate statistical method (MANOVA). The second aim was to estimate the volume growth of Shafa-Rud forest basin. Two northern and southern aspects were chosen in the middle latitude profile (800-1200 m.a.s.l) and on each aspect, 30 circular sampling plots were selected using the random blocking method. In each sample plot, six trees were chosen according to a predefined model for sampling the radial growth using an increment borer and for measuring other quantitative variables such as height of trees and diameter at breast height (DBH). Weighted local volume tables were calculated for each of the ecological aspects and were compared using t-test. Multivariate statistical analysis, Hotelling`s T22 test, which was carried out on means vector of the four quantitative variables: diameter, height, bark thickness and radial growth, demonstrated that the difference in centroid of vectors was highly significant. The stand volume growths in the southern and northern aspects were found to be 9.2 and 9.5 sylve per hectare, respectively.

Influence of landscape heterogeneity on spatial patterns of wood productivity, wood specific density and above ground biomass in Amazonia
About this Resource: Long-term studies using the RAINFOR network of forest plots have generated significant insights into the spatial and temporal dynamics of forest carbon cycling in Amazonia. In this work, we map and explore the landscape context of several major RAINFOR plot clusters using Landsat ETM+ satellite data. In particular, we explore how representative the plots are of their landscape context, and test whether bias in plot location within landscapes may be influencing the regional mean values obtained for important forest biophysical parameters. Specifically, we evaluate whether the regional variations in wood productivity, wood specific density and above ground biomass derived from the RAINFOR network could be driven by systematic and unintentional biases in plot location. Remote sensing data covering 45 field plots were aggregated to generate landscape maps to identify the specific physiognomy of the plots. In the Landsat ETM+ data, it was possible to spectrally differentiate three types of &lt;i&gt;terra firme&lt;/i&gt; forest, three types of forests over Paleovarzea geomorphologycal formation, two types of bamboo-dominated forest, palm forest, &lt;i&gt;Heliconia&lt;/i&gt; monodominant vegetation, swamp forest, disturbed forests and land use areas. Overall, the plots were generally representative of the forest physiognomies in the landscape in which they are located. Furthermore, the analysis supports the observed regional trends in those important forest parameters. This study demonstrates the utility of landscape scale analysis of forest physiognomies for validating and supporting the finds of plot based studies. Moreover, the more precise geolocation of many key RAINFOR plot clusters achieved during this research provides important contextual information for studies employing the RAINFOR database.

Response of forest vegetation to varying levels and patterns of green-tree retention: An overview of a long-term experiment
About this Resource: Timber harvest with retention of live ("green") trees, snags, and logs is now a standard practice on federal "matrix" lands within the range of the northern spotted owl. Although specific guidelines have been adopted for the levels and spatial configurations of retained structures, neither the ecological assumptions that underlie these recommendations nor the outcomes of these practices have been rigorously tested. The Demonstration of Ecosystem Management Options (DEMO) study examines the responses of forest ecosystems in the Pacific Northwest to varying levels (percentage of basal area) and patterns (dispersed versus aggregated) of green-tree retention. In this paper we describe vegetation studies that form the foundation of this long-term, interdisciplinary experiment. We review the results of retrospective analyses and simulation models which suggest that even minimal levels of retention may have important effects on forest development. We describe the characteristics of the DEMO sites, the experimental design, and the principal variables of interest (stand structure, tree regeneration and growth, and understory composition and diversity). We speculate about the silvicultural and ecological responses of forests to varying levels and patterns of retention and focus in particular on the dynamics of the forest understory. We anticipate strong contrasts among treatments in the establishment of early-seral, open-site species, and in the persistence of shade-tolerant plants associated with older forests or forest-interior environments. Short-term responses are likely to be driven by variation in the distribution and intensity of harvest disturbance. Longer-term trends are expected to reflect the effects of contrasting patterns of canopy retention. We conclude by discussing some of the scientific challenges faced in designing and implementing large-scale, interdisciplinary experiments

Wild birds as hosts of Amblyomma cajennense (Fabricius, 1787) (Acari: Ixodidae)
About this Resource: We evaluated the prevalence, mean intensity and relative density of ticks in 467 wild birds of 67 species (12 families) from forest and cerrado habitats at two protected areas of Minas Gerais, between March and September 1997. Ticks collected (n=177) were identified as larvae and nymphs of Amblyomma cajennense and four other species of Amblyomma. We report for the first time 28 bird species as hosts of the immature stages of A. cajennense, demonstrating the lack of host specificity of the larvae and nymphs. A. cajennense had 15% prevalence on birds, with a mean infestation intensity of 0.37 ticks per host sampled, and 2.5 ticks per infested bird. Prevalence varied in relation to host species, diet and between birds from forests at two successional stages. There were no differences in relation to host forest dependence, participation in mixed flocks of birds, and nest type constructed. A. cajennense is a species of medical and veterinary importance, occurring on domestic animals but is known little of its occurrence on wildlife.

Gas-particle interactions above a Dutch heathland: III. Modelling the influence of the NH3-HNO3-NH4NO3 equilibrium on size-segregated particle fluxes
About this Resource: Micrometeorological measurements of size-segregated particle number fluxes above Dutch heathlands and forests have repeatedly shown simultaneous apparent emission of particles with a diameter (Dp)3), nitric acid (HNO3) and ammonium (NH4+), a new numerical model is developed to predict the vertical concentration and flux profiles of the different species as modified by the interaction of equilibration and surface/atmosphere exchange processes. In addition to former studies, the new approach explicitly models the height-dependence of the NH4+ and total aerosol size-distribution. Using this model, it is demonstrated that both gas-to-particle conversion (gtpc) and aerosol evaporation can significantly alter the apparent surface exchange fluxes, and evoke the observed bi-directional particle fluxes under certain conditions. Thus, in general, the NH3-HNO3-NH4NO3 equilibrium needs to be considered when interpreting eddy-covariance particle fluxes. Applied to an extensive dataset of simultaneous flux measurements of particles and gases at Elspeet, NL, the model reproduces the diurnal pattern of the bi-directional exchange well. In agreement with the observation of fast NH4+ deposition, slow nitric acid deposition (both as measured by the aerodynamic gradient method) and small concentration products of NH3&times;HNO3 at this site, this study suggests that NH4+ evaporation at this site significantly alters surface exchange fluxes.

TRADEOFFS BETWEEN RURAL DEVELOPMENT POLICIES AND FOREST PROTECTION: SPATIALLY-EXPLICIT MODELING IN THE CENTRAL HIGHLANDS OF VIETNAM
About this Resource: Alleviating rural poverty remains an important objective of development policy in many areas of the world. However, traditional means of increasing rural livelihoods such as increased investments in agricultural intensification measures can have disastrous impacts on natural resources such as forests by greatly increasing incentives for clearing. This paper contains a spatially-explicit model of land use in the Dak Lak province in the Central Highlands of Vietnam. Land use is modeled using a reduced-form multinomial logit model, and policy simulations are conducted. These simulations demonstrate that the adoption of yield-increasing inputs requires concomitant forest protection policies, both in terms of forest area and spatial configuration.

Between Conservationism, Eco-Populism and Developmentalism: Discourses in Biodiversity Policy in Thailand and Indonesia
About this Resource: The present paper analyzes the role of discourse in conflicts concerning nature conservation in tropical countries. We focus on the contested question as to whether and to which extent local communities should be allowed to live and use resources inside protected areas. Applying the concepts of belief-systems, story-lines and discourse coalitions, we analyze two empirical case studies dealing with this conflict: The first case study is concerned with a policy process at the national level that aimed at passing a community forestry law in Thailand to make the establishment of community forests in protected areas possible. The second case study deals with the proposed resettlement of a village from the Lore Lindu National Park in Sulawesi, Indonesia. In both cases, three discourses could be observed: a conservationist discourse, an eco-populist discourse, and a developmentalist discourse. The case studies show that the conservationists and the developmentalists were able to form a discourse coalition, which was challenged by the proponents of the eco-populist discourse. The analysis also demonstrates that establishing storylines in the discourse can lead to the neglect of facts and problems that do not fit in either discourse. The paper draws attention to the role of science in the different discourses and concludes that scientists should become more aware of the role they play in the different discourses.

Forestry and the Carbon Market Response to Stabilize Climate
About this Resource: This paper investigates the potential contribution of forestry management in meeting a CO2 stabilization policy of 550 ppmv by 2100. In order to assess the optimal response of the carbon market to forest sequestration we couple two global models. An energy-economy-climate model for the study of climate policies is linked with a detailed forestry model through an iterative procedure to provide the optimal abatement strategy. Results show that forestry is a determinant abatement option and could lead to significantly lower policy costs if included. Linking forestry management to the carbon market has the potential to delay the policy burden, and is expected to reduce the price of carbon of 40% by 2050. Biological sequestration will mostly come from avoided deforestation in tropical forests rich countries. The inclusion of this mitigation option is demonstrated to crowd out some of the traditional abatement in the energy sector and to lessen induced technological change in clean technologies.

Wildland fire in Eastern Oregon and Washington
About this Resource: Wildland fire is a major disturbance agent that shapes the forest health, productivity, and ecological diversity of eastern Oregon and Washington, USA. Fire behaviour and the effects of fire on flora, fauna, soils, air, and water are in large part driven by the availability of fuels to consume and the meteorological influences during a fire. Vegetation succession, disturbance processes, and management practices have resulted in an increase of fuels and vulnerability to extreme fire behaviour and detrimental fire effects. Hazards of fire are further increased by encroachment of dwellings into forests and rangelands. Prescribed fire, selective logging, and mechanical fuel treatment are being used to reduce fire hazard, but there is disagreement as to appropriate balance and efficacy of these actions. New tools to (1) characterize fuelbeds; (2) predict mesoscale meteorology, fire behaviour, fire effects, smoke production, and dispersal; and (3) demonstrate tradeoffs between prescribed fire and other fuel treatment methods are continually being improved to assist with wildland fire and prescribed fire decision making in eastern Oregon and Washington.

Using tropical forest ecosystem goods and services for planning climate change adaptation with implications for food security and poverty reduction
About this Resource: Tropical forest ecosystems represent a common heritage with livelihood portfolios shared by a great majority of people especially in developing countries but are now threatened by climate change. In spite of their contribution to poverty alleviation and food security, and also for climate change responses (adaptation and mitigation especially through the market-incentive schemes (CDM) of the Kyoto Protocol) forests are still hardly integrated into national planning processes aimed at addressing any of these national development challenges. This is evident in some of the national documents of some developing countries such as the Poverty Reduction Strategy Paper (PRSP) to the World Bank, and the First National Communication to UNFCCC. This paper presents some preliminary outcomes of the Tropical Forests and Climate Change Adaptation (TroFCCA) project of the Center for International Forestry Research (CIFOR) whose overall mission is to underscore the importance of tropical forests for livelihood adaptation to climate change and mainstreaming adaptation into national development processes. The paper also highlights TroFCCA’s approach in engaging stakeholders from the onset in setting the agenda with the identification and prioritization of forest-based sectors as the entry point in the process of assessing the vulnerability to climate change and developing adaptation strategies for these selected development sectors. This is a highly crucial area with great policy implications. Planning with ecosystem goods and services seems to emerge as a prospective approach to demonstrate to policymakers the potential of forest ecosystems for livelihood adaptation to climate change which also enhances the opportunity for achieving food security and community resilience to poverty. TroFCCA’s approach in engaging stakeholders at the onset in defining their perception of ecosystem goods and services by virtue of their importance to household livelihoods and their contribution to national development emphasizes the significance of a place-based context in the valuation of ecosystem goods and services. This approach also contributes to raising public and policy awareness to climate change as part of the continuum of mainstreaming climate change adaptation into national development planning. The study also highlights the opportunities that an ecosystem approach provides for integrated natural resource planning for achieving co-benefits linked to the realization of two (1 and 7) important Millennium Development Goals. However, there are other policy and institutional reform challenges including governance, equity and rights to resources that need to be addressed in order to reap the full suite of benefits for climate change adaptation, poverty reduction and food security.

MAMÍFEROS NÃO-VOADORES DE UM FRAGMENTO DE MATA MESÓFILA SEMIDECÍDUA, DO INTERIOR DO ESTADO DE SÃO PAULO, BRASIL
About this Resource: Semideciduous forests from rural areas of São Paulo State are isolated and small due to agriculture, industry and city growth. Fragmented forests are important to the persistence of several mammal species. In this study we did an inventory of the mammal fauna from a fragmented mesophilous semideciduous forest in the rural regionof the São Paulo State (Fazenda São José), between Rio Claro and Araras cities. In the three sampling periods, between May 1997 and March 1999, field work was done using traps for small mammals, direct observation of animals and identification of their footprints. We recorded the occurrence of three marsupial species (Didelphidae), twoarmadillos (Dasipodidae), three primates (Callithrichidae and Cebidae), five carnivores (Canidae, Procyonidae and Mustelidae), one deer (Cervidae), six rodent (Sciuridae and Muridae) and one rabbit (Leporidae). Didelphis albiventris (Didelphidae), Nectomys squamipes and Akodon montensis (Muridae) were the most frequently species captured. Mammal species of the study area are also present in other areas of Atlantic Forest in São Paulo State and others mesophilous forests from of the region around. However, we did not captured or observed signs of rodents and felid species common to other areas linked to the study area through gallery forest of the Ribeirão Claro (Rio Claro city). The forest studied showed a subset of mammal species present in other larger areas of the region, and the mammal species listed in this area demonstrated how it is important theconservation of this and other forest fragments to mammal diversity in the State. = As florestas semidecíduas do interior do Estado de São Paulo são isoladas e pequenas devido às atividades agrícolas, expansão urbana e industrial. Os remanescentes dos fragmentos florestais são importantes para a persistência de diversas espécies demamíferos. Neste estudo foi feito um inventário da mastofauna de um fragmento de mata mesófila semidecídua no interior do Estado (Fazenda São José) nos municípios de Rio Claro e Araras. Nos três períodos amostrados, entre maio de 1997 e março de 1999, o levantamento da mastofauna foi feito por meio de armadilhas para pequenos mamíferos,bem como de observação direta e identificação de rastros dos animais. Registrou-se a ocorrência de três espécies de marsupiais (Didelphidae), duas de tatus (Dasipodidae), três de primatas (Callithrichidae e Cebidae), cinco de carnívoros (Canidae, Procyonidae e Mustelidae), uma de veado (Cervidae), sete de roedores (Sciuridae e Muridae) e uma de coelho (Leporidae). Didelphis albiventris (Didelphidae), Nectomys squamipes e Akodon montensis (Muridae) foram as espécies com maior número de indivíduos coletados. A mastofauna da área estudada apresenta espécies comuns a outras áreas de Mata Atlântica do interior do Estado de São Paulo e a outras áreas de floresta mesófila da mesma região. Entretanto, não foram capturadas ou avistadas espécies de roedores e felinos comuns emoutras áreas de mata que estão ligadas a área estudada pela mata ciliar do Ribeirão Claro (município de Rio Claro). O fragmento de mata estudado apresenta ainda um subconjunto da mastofauna que ocorre nas áreas maiores da região, sendo a conservação deste e de outros fragmentos de mata importante para a manutenção da diversidade de mamíferos no Estado.

Silvicultural Activities in Relation to Water Quality in Texas: An Assesment of Potential Problems and Solutions
About this Resource: Southern forests are expected to supply a large portion of the Nation's future timber requirement. Projected demands on southern forests continue to exceed allowable cut. As an outgrowth of this demand, intensive management of pine forests enabled the South to produce 45 percent of the Nation's timber harvest in 1970 (USDA, Forest Service, 1973). The Southern Forest Resource Analysis Committee (1969) stated that, if projected timber needs of the year 2000 are to be met, at least ten million acres of bare or poorly stocked land must be planted with pine by 1985 and another twenty million acres converted from low-grade hardwoods to pine. The challenge facing forestry in the South is how to meet this increased demand and maintain an acceptable forest environment in the face of increased taxes, rising labor and equipment costs and predicted petroleum shortages. Undisturbed forests are generally recognized as primary sources of high quality water. Although the Federal Water Pollution Control Act Amendments of 1972 (Public Law No. 92-500) make pollution from forest practices increasingly more important, the effects of these practices on water quality are not known for East Texas. The quality of streamflow from forested watersheds fluctuates constantly in response to natural stress, and can be influenced greatly by man's activities. Forest management practices can potentially influence the following water quality parameters: (1) sediment, (2) nutrients, (3) temperature, (4) dissolved oxygen/organic matter, and (5) introduced chemicals. It must be realized from the onset that sediment due to geologic erosion is a natural component of fresh water streams and that high concentrations may have occurred naturally for short periods due to perturbations in the ecosystem such as wildfires. Sediment is not necessarily a pollutant and only becomes one when it can be demonstrated that it is exceeding natural levels and is interfering with the beneficial use of water. A certain amount of sediment and nutrients are needed in Gulf Bays and Estuaries to maintain their productivity (Mathewson and Minter, 1976; Diener, 1964; Ketchum, 1967). Texas does not have a stream water quality standard for sediment and due to the complexities involved will probably not develop one. Thus, sediment as used in this report, becomes important: (1) as a carrier of plant nutrients and forest chemicals, and (2) in that practices which reduce sediment loss will usually reduce nutrient, organic matter and introduced chemical losses and prevent water temperature increases, as well. This report is the result of an interagency contract between Texas Department of Water Resources, Texas Agricultural Experiment Station and Texas Water Resources Institute to: (1) develop an overview of commercial forests and forestry operations in Texas, (2) identify, describe and characterize control strategies for nonpoint sources of pollution from silvicultural activities, and (3) develop and demonstrate a methodology for selecting control strategies in given problem situations. The following topics are covered: (1) an overview of forestry in East Texas, (2) silvicultural practices and nonpoint sources of pollution, (3) control strategies, (4) methodology for the selection of control strategies, (5) institutional aspects of controlling silvicultural nonpoint source pollution, (6) ongoing research and research needs, and (7) hydrology of East Texas. It is important to recognize that this report does not specify that nonpoint pollution from forestlands in East Texas is a problem. Likewise, the report does not set pollution control goals or criteria that should be met by a control plan, since this is the responsibility of the State. In areas where a potential nonpoint pollution problem exists; the suggested control strategies should be useful in selecting control measures that are appropriate to the special conditions imposed by differences in climate, soil, topography, and forest practice.

Estimating Carbon Supply Curves for Global Forests and Other Land Uses
About this Resource: This study develops cumulative carbon “supply curves” for global forests utilizing an dynamic timber supply model for sequestration of forest carbon. Because the period of concern is the next century, and particular time points within that century, the curves are not traditional Marshallian supply curves or steady-state supply curves. Rather, the focus is on cumulative carbon cost curves (quasi-supply curves) at various points in time over the next 100 years. The research estimates a number of long-term, cumulative, carbon quasi-supply curves under different price scenarios and for different time periods. The curves trace out the relationship between an intertemporal price path for carbon, as given by carbon shadow prices, and the cumulative carbon sequestered from the initiation of the shadow prices, set at 2000, to a selected future year (2010, 2050, 2100). The timber supply model demonstrates that cumulative carbon quasi-supply curves that can be generated through forestry significantly depend on initial carbon prices and expectations regarding the time profile of future carbon prices. Furthermore, long-run quasisupply curves generated from a constant price will have somewhat different characteristics from quasisupply curves generated with an expectation of rising carbon prices through time. The “least-cost” curves vary the time periods under consideration and the time profile of carbon prices. The quasi-supply curves suggest that a policy of gradually increasing carbon prices will generate the least costly supply curves in the shorter periods of a decade or so. Over longer periods of time, however, such as 50 or 100 years, these advantages appear to dissipate.

Pedunculate oak forests (Quercus robur L.) survey in the Ticino Regional Park (Italy) by remote sensing
About this Resource: Pedunculate oak forests (Quercus robur L.) in the Ticino Regional Park (Italy) show sensible damage conditions due to different environmental stresses: insect attacks, summer drought and air pollution. Knowing whether oaks are healthy or stressed can provide useful information in order to conserve the forest ecosystems and avoid the lost of valuable natural resources. Environmental stresses can affect tree biochemical and structural variables, such as the concentration, composition and efficiency in light harvesting of foliar pigments, and the Leaf Area Index (LAI). Interest in the use of these variables for forest condition assessment has recently increased because they can be indirectly estimated from remote observations at leaf and canopy level. In particular, in this research we found that total chlorophyll (Chl) concentration, a biochemical variable related to crown discoloration rate, was the most suitable variable for the detection of pedunculate oak decline in the Ticino Park. A regression analysis between Chl concentration and optical indices computed from hyperspectral MIVIS data was performed in order to estimate Chl concentration from remote observations. The good correlation between field measurements of Chl concentration and MIVIS optical indices allowed the development of a model to map Chl concentration across the Ticino Park forested area. Promising results demonstrated that remotely sensed data can provide an accurate estimation of Chl concentration and indicated the potential of this technique for forest condition monitoring.

Two mycoheterotrophic orchids from Thailand tropical dipterocarpacean forests associate with a broad diversity of ectomycorrhizal fungi
About this Resource: Abstract Background Mycoheterotrophic plants are considered to associate very specifically with fungi. Mycoheterotrophic orchids are mostly associated with ectomycorrhizal fungi in temperate regions, or with saprobes or parasites in tropical regions. Although most mycoheterotrophic orchids occur in the tropics, few studies have been devoted to them, and the main conclusions about their specificity have hitherto been drawn from their association with ectomycorrhizal fungi in temperate regions. Results We investigated three Asiatic Neottieae species from ectomycorrhizal forests in Thailand. We found that all were associated with ectomycorrhizal fungi, such as Thelephoraceae, Russulaceae and Sebacinales. Based on 13C enrichment of their biomass, they probably received their organic carbon from these fungi, as do mycoheterotrophic Neottieae from temperate regions. Moreover, 13C enrichment suggested that some nearby green orchids received part of their carbon from fungi too. Nevertheless, two of the three orchids presented a unique feature for mycoheterotrophic plants: they were not specifically associated with a narrow clade of fungi. Some orchid individuals were even associated with up to nine different fungi. Conclusion Our results demonstrate that some green and mycoheterotrophic orchids in tropical regions can receive carbon from ectomycorrhizal fungi, and thus from trees. Our results reveal the absence of specificity in two mycoheterotrophic orchid-fungus associations in tropical regions, in contrast to most previous studies of mycoheterotrophic plants, which have been mainly focused on temperate orchids.